1. Field of the Invention
The present invention relates to a laminated piezoelectric transducer, more specifically, to a laminated piezoelectric transducer formed by laminating a number of piezoelectric plates, which laminated expands and contracts upon application of an electrical voltage and can be used as an actuator.
2. Description of the Related Art
Known in the prior art is a laminated piezoelectric transducer actuator wherein piezoelectric plates and metal electrode plates having extrusions in three directions are alternatively laminated, the extrusion extruding from the laminate of the piezoelectric plates. In this actuator, the metal electrode plates are connected at the extrusions in parallel by outer leads or outer electrodes, and these metal electrode plates and metal coatings formed on the main surfaces of the piezoelectric plates are made within the main surfaces of the piezoelectric plates and apart from the periphery of the piezoelectric plates, to prevent a short circuit caused by contact between the side leads and the metal electrode plates or the metal coatings having opposite potentials (see, for example, Japanese Unexamined Patent Publication (Kokai) No. 60-4279 and U.S. Pat. No. 4,011,474 to O'Neill).
Recently, such actuators are often used for high load operations. This necessitates an actuator having electrodes covering the entire surfaces of piezoelectric plates, to ensure an effective utilization of the entire area of the piezoelectric plates or the actuator, and from the viewpoint that the coexistence of a loaded portion and a portion not under a load should be avoided.
Further, to lower the cost of a drive circuit, the voltage to be applied should be lowered, but if the thickness of piezoelectric elements or plates is reduced for this purpose, the mechanical strength of the piezoelectric plates is decreased to an extent such that a laminate of such thin piezoelectric plates having metal electrode plates inserted therebetween, will split.